8 September 2017

K4MT/NT9P Net, Russian Intel/Diplo (M42b)

K4MT/NT9P network, also known as Enigma designator M42b, is a quite common Russian Intel/Diplo network which uses both CW-Morse and FSK 50Bd/500.

Fig. 1

In this recording, FSK follows a CW call "NT9P NT9P NT9P DE K4MT K4MT K" and in turn it's followed by a "CFM QRU K" request: most likely the CW is used for setup or operators chat. The FSK is a Baudot 5FG coded stream using a preamble and 7-bit period (fig. 2):